It bore through Niagara suddenly and ferociously on Tuesday afternoon and in a matter of minutes left many of Niagara’s grapevines pockmarked and damaged.

Hail is one of the most feared calamities, among many for tender fruit growers, because of the considerable damage it can cause so quickly, without warning and without a defence to prevent it.

Reports of damage came in from most parts of Niagara wine country, but the worst seemed to have occurred along the Niagara Escarpment benches, in particular the Beamsville Bench.

On the Twenty Mile Bench Wednesday, I took a stroll through Vineland Estates’ premier Bo-Teek Vineyard with winemaker Brian Schmidt. While the damage wasn’t immediately evident, once Schmidt started pointing out immature grape bunches lying lifeless on the ground the situation became clearer.

The flash hailstorm left damage, not severe damage, but enough to cause concern for Schmidt as he surveys the estate’s vineyards and gets reports from fellow grape growers.

Damage to the leaves, some left with holes and torn edges, is less of a concern than cuts to thin-barked vines that can compromise the bark of the vine. A wound is considered any break in the outer protective bark of the trunk that exposes the xylem. After this occurs, new space and nutrients become available to a number of organisms, including insects and pathogens.

Looking closer at the vines at Bo-Teek you can see where the hail stones had severed some branches of the vines and also damaged grape bunches wholly or partially, which, either way, will reduce yield come harvest time.

Schmidt called the rare hail episode, which he says hasn’t occurred in ten years, significant but “not catastrophic.” In all, about 10% of the Bo-Teek Vineyard was affected by the storm.

Because Schmidt and his team had not leaf thinned at all, providing an umbrella over and around the fruit, damage was kept to a minimum. He leaves the canopy for as long as he can “exactly for that reason” — in the event of hail, to act as partial protection.

A few other growers around Niagara had performed some sort of thinning and likely suffered a bit more damage because of it.

When hail damage occurs to fruit, the results can be devastating. Damage during early stages of fruit set can cause scarring or berry loss. Hail at (or after) veraison will lead to fruit rot. Defoliation also may occur from hail and in severe instances can lead to a delay in fruit maturation and excess lateral shoot development.

After a cool, extremely wet spring in Niagara, a hailstorm was last thing grape growers needed.